(a) Field of the Invention
The present invention relates to an apparatus for driving a display device, a driving method for the apparatus and a display device having the apparatus. More particularly, the present invention relates to an apparatus and driving method thereof for a display device having reduced electromagnetic interference (“EMI”).
(b) Description of the Related Art
Generally, a liquid crystal display (“LCD”) includes a first panel having pixel electrodes and a second panel having a common electrode, and a liquid crystal layer with dielectric anisotropy interposed therebetween. The pixel electrodes are arranged in a substantially matrix pattern, and are each connected to a switching element such as a thin film transistor (“TFT”) through which data signals are sequentially applied to rows of the pixel electrodes. A common voltage is applied to the common electrode, which extends over substantially an entire area of a surface of the second panel. Thus, each individual pixel electrode and the common electrode, having the liquid crystal layer disposed therebetween, form a liquid crystal capacitor. A switching element, e.g., the TFT, connected to the liquid crystal capacitor forms a basic unit for a pixel of the LCD.
Voltages applied to the first panel and the second panel, e.g., the data voltages applied to the pixel electrodes and the ground voltage applied to the common electrode, generate an electric field in the liquid crystal layer. Varying an intensity of the electric field controls a transmittance of light passing through the liquid crystal layer, thereby displaying a desired image. To prevent the liquid crystal layer from deteriorating due to continual application of a unidirectional electric field, a voltage polarity of the data signal with respect to the common voltage is inverted for every frame, pixel or pixel row, for example.
Most display devices, including LCDs, have problems of electromagnetic interference (“EMI”), particularly in LCDs with increased operating frequencies, for example. Thus, it is desired to develop a display device having reduced EMI.